What symbol do the Franks and Van Daans wear on their clothes during the play?

The Franks and Van Daans begin the play wearing yellow Star of David badges with the word "Jude" (German for "Jew") printed in the middle. During the rise of Hitler's Third Reich, Jewish people in Nazi-occupied countries were required to wear these badges to mark that they were Jewish and should be treated differently. Jewish people had to affix these badges onto all of their clothes and would be penalized if they were caught not wearing the badges. As the Nazi party's control tightened, Jewish people were not allowed to go to spaces such as movie theaters, restaurants, stores, and public swimming pools. Business owners could see the Star of David badges and deny entry to any Jewish people trying to enter.
The Franks and Van Daans are wearing these badges not only because it is historically accurate, but also because it shows us how dire the situation has become in Amsterdam and why they need to hide.